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US-12626949-B2 - Solid electrolyte, solid electrolyte layer and solid electrolyte battery

US12626949B2US 12626949 B2US12626949 B2US 12626949B2US-12626949-B2

Abstract

A solid electrolyte includes a compound composed of an alkali metal, at least one metal element selected from Zr, Hf, Ti, Sn, Mg, Ca, Sr, Cs, Ba, Y, Al, Sc, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Cu, Ag, Au, Pb, Bi, In, Sn, Sb, Nb, Ta and W and an element belonging to Group XVII of the periodic table.

Inventors

  • Hisashi Suzuki
  • Tetsuya Ueno

Assignees

  • TDK CORPORATION

Dates

Publication Date
20260512
Application Date
20200720
Priority Date
20190807

Claims (8)

  1. 1 . A solid electrolyte comprising a compound represented by the following formula (1), A 2+a E 1-b+α G b X d (1) where: A is one element selected from the group consisting of Li, K and Na, E is at least one element selected from the group consisting of Zr, Hf, Ti and Sn, X is Cl a is zero in a case where G is not contained, b is zero, −0.3≤α≤0.3, and 5.7≤d≤5.8.
  2. 2 . The solid electrolyte according to claim 1 , wherein, in the compound represented by the formula (1), A is Li, E is Zr, and X is Cl.
  3. 3 . The solid electrolyte according to claim 1 , wherein the compound represented by the formula (1) is a compound represented by the following formula (2), Li 2 ZrCl d-e I e (2) where: 5.7≤d≤5.8, and e is zero.
  4. 4 . The solid electrolyte according to claim 1 , further comprising: 0.05 to 1.0 mass % of at least one compound selected from the group consisting of: A 2 O, where A is one element selected from the group consisting of Li, K and Na; AX, where A is one element selected from the group consisting of Li, K and Na, and X is at least one selected from the group consisting of F, Cl, Br and I; EO 2 , where E is at least one element selected from the group consisting of Zr, Hf, Ti and Sn; EX 4 , where E is at least one element selected from the group consisting of Zr, Hf, Ti and Sn, and X is at least one selected from the group consisting of F, Cl, Br and I; and GO n , where: G is at least one element selected from the group consisting of Mg, Ca, Sr, Cs, Ba, Al, Sc, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Cu, Ag, Au, Pb, Bi, In, Sn, Sb, Nb, Ta and W, and n is: 0.5 in a case where G is a monovalent element, 1 in a case where G is a divalent element, 1.5 in a case where G is a trivalent element, 2 in a case where G is a tetravalent element, 2.5 in a case where G is a pentavalent element, and 3 in a case where G is a hexavalent element.
  5. 5 . A solid electrolyte layer comprising: the solid electrolyte according to claim 1 .
  6. 6 . A solid electrolyte battery comprising: a solid electrolyte layer; a positive electrode; and a negative electrode, wherein at least one of the solid electrolyte layer, the positive electrode and the negative electrode contains the solid electrolyte according to claim 1 .
  7. 7 . A solid electrolyte battery comprising: a solid electrolyte layer; a positive electrode; and a negative electrode, wherein the solid electrolyte layer contains the solid electrolyte according to claim 1 .
  8. 8 . A solid electrolyte comprising a compound represented by the following formula (1), A 2+a E 1-b+α G b X d (1) where: A is one element selected from the group consisting of Li, K and Na, E is at least one element selected from the group consisting of Zr, Hf, Ti and Sn, G is Nb, X is at least one selected from the group consisting of F, Cl, Br and I, a is-b in a case where G is a pentavalent element, and 0≤b≤0.5, −0.3≤α≤0.3, and 5.0<d<6.0.

Description

TECHNICAL FIELD The present invention relates to a solid electrolyte, a solid electrolyte layer and a solid electrolyte battery. The present application claims priority on Japanese Patent Application No. 2019-145664 filed in Japan on Aug. 7, 2019, the content of which is incorporated herein by reference. BACKGROUND ART In recent years, developments in electronics technology have been significant, and the size reduction, weight reduction, thickness reduction, and multi-functionalization of mobile electronic devices have been achieved. Accordingly, for batteries that serve as power sources of electronic devices, there is a strong demand for size reduction, weight reduction, thickness reduction, and reliability improvement. Therefore, solid electrolyte batteries in which a solid electrolyte is used as an electrolyte are gaining attention. As the solid electrolyte, oxide-based solid electrolytes, sulfide-based solid electrolytes, complex hydride-based solid electrolytes (LiBH4 and the like) and the like are known. Patent Document 1 discloses a solid electrolyte secondary battery having a positive electrode including a positive electrode layer containing a positive electrode active material containing a Li element and a positive electrode current collector, a negative electrode including a negative electrode layer containing a negative electrode active material and a negative electrode current collector and a solid electrolyte that is sandwiched between the positive electrode layer and the negative electrode layer and is composed of a compound represented by the following general formula. Li3-2XMXIn1-YM′YL6-ZL′Z (In the formula, M and M′ are metal elements and L and L′ are halogen elements. In addition, X, Y and Z independently satisfy 0≤X≤1.5, 0≤Y≤1 and 0≤Z≤6.) Patent Document 2 discloses a solid electrolyte material represented by the following composition formula (1). Li6-3ZYZX6  Formula (1) wherein 0<Z<2 is satisfied, and X is Cl or Br. In addition, Patent Document 2 describes a battery in which at least one of a negative electrode and a positive electrode contains the solid electrolyte material. Patent Document 3 discloses a solid electrolyte battery including an electrode active material layer including an active material, a first solid electrolyte material that is in contact with the active material, has an anion component different from an anion component of the active material and is a single-phase electron-ion mixed conductor and a second solid electrolyte material that is in contact with the first solid electrolyte material, has the same anion component as the anion component in the first solid electrolyte material and is an ion conductor having no electron conductivity. In addition, Patent Document 3 discloses that the first solid electrolyte material is Li2ZrS3, the first solid electrolyte material has a peak of Li2ZrS3 at 2θ=34.2°±0.5° in X-ray diffraction measurement using CuKα rays, and, in a case where the diffraction intensity of the peak of Li2ZrS3 at 2θ=34.2°±0.5° is indicated by IA and the diffraction intensity of the peak of ZrO2 at 2θ=31.4°±0.5° is indicated by IB, the value of IB/IA is 0.1 or less. PRIOR ART DOCUMENTS Patent Document Patent Document 1: Japanese Unexamined Patent Application, First Publication No. 2θ06-244734Patent Document 2: PCT International Publication No. WO 2018/025582Patent Document 3: Japanese Unexamined Patent Application, First Publication No. 2θ13-257992 DISCLOSURE OF INVENTION Problems to be Solved by the Invention However, in conventional solid electrolyte batteries, solid electrolytes that were used in solid electrolyte layers had insufficient ionic conductivity. Therefore, in conventional solid electrolyte batteries, it was not possible to obtain a sufficient discharge capacity. The present invention has been made in consideration of the above-described problem, and an object of the present invention is to provide a solid electrolyte having a high ionic conductivity. In addition, another object of the present invention is to provide a solid electrolyte layer including the above-described solid electrolyte and a solid electrolyte battery with a large discharge capacity including the solid electrolyte layer. Solutions for Solving the Problems The present inventors performed intensive studies in order to solve the above-described problem. As a result, the present inventors found that a compound composed of an alkali metal, a specific metal element and an element belonging to Group XVII of the periodic table is preferably used as a solid electrolyte and obtained an idea of the present invention. That is, the present invention relates to the following inventions. [1] A solid electrolyte including a compound represented by the following formula (1). A2+aE1−b+aGbXd  (1) (In the formula (1), A is one element selected from the group consisting of Li, K and Na. E is at least one element selected from the group consisting of Zr, Hf, Ti and Sn. G is at least one elem